The present invention relates generally to coupling devices for connecting a tractor or other similar prime mover to a hitch-mounted implement, and more particularly to a quick-attaching coupler and power takeoff apparatus for automatically coupling a hitch-mounted implement and engaging the power takeoff.
Quick attaching couplers have been developed to allow faster attachment of hitch mounted implements to a tractor. Many quick attaching couplers comprise an inverted U-shape arched frame that is attached to the conventional three pivot points of a tractor hitch. The quick attaching coupler frame includes an upper hook with a long, tapered point and two lower coupling hooks or jaws with a latching and unlatching arrangement to hold the implement hitch pins. To couple an implement using the quick coupler, the coupler is lowered by positioning the tractors three point hitch and the tractor positioned near the implement with the coupling hooks adjacent the implement hitching pins. Then the hitch and connected quick coupler is then raised with the tractor hydraulic system so that the upper hook begins to engage the upper pin on the implement Further lifting, assuming all three connection points are aligned, causes the weight of the implement to force the lower hitch pins to enter the lower hooks where they may be latched in place by the tractor operator to secure the implement.
The latches may be spring loaded to the locked or latched position. Locking the latches may be accomplished by having the operator dismount the tractor seat to manually operate two locking mechanisms for the two hitch pins. Some quick attaching couplers incorporate one or more levers that enable the operator to remain seated on the tractor while locking the latches.
Tractors may be equipped with a power take off (hereinafter “PTO”) drive that provides a mechanism for transmitting rotary power from the engine to implements that are coupled to a tractor The PTO is most commonly a rotating splined shaft which projects rearwardly from the rear of the tractor frame for a short distance; however, some tractors have auxiliary PTO shafts at other locations, such as at the front of the tractor. The direction of rotation, rotational speed, approximate location and exact dimensions of the PTO shaft are standardized to provide the ability to interchange between power shafts of various implements made by different manufacturers. The PTO shaft of a tractor is typically driven at either 540 rpm or 1,000 rpm. It is well understood in this field of invention that the PTO shaft rpm varies with engine speed and the rotational speeds of 540 rpm and 1,000 rpm are typically the standard “rated” speeds for PTO driven implements. Although the PTO described herein projects rearwardly from the tractor, it should be appreciated that the invention described relates to any PTO, regardless of location on a prime mover.
Most hitch-mounted implements have a driveline comprised of a telescoping, splined drive shaft which can be extended to connect at one end to the splined interface of the tractors PTO while the other end connects to the rotary input connection (typically a gearbox input) for the implement. The driveline typically includes two or more universal or constant velocity joints, or the like, to allow angular movement of the implement and tractor relative to one another without binding the driveline.
Connecting the PTO driveline assembly to the tractor PTO can be cumbersome, especially in the case of three point hitch-mounted implements which may have limited accessibility to the PTO connection area. The object of a quick attaching coupler is to simplify the process of connecting an implement to a tractor hitch; however, requiring an operator to manually connect the PTO imposes a sometimes difficult and time-consuming task in the hitching process thereby diminishing some benefits of the quick attaching coupler. Connecting the driveline generally requires that the implement drive shaft be lifted into position for engaging the PTO splined connection. The drive shaft must often be manually rotated to align the splines while simultaneously holding the weight of the driveline assembly. This task is time consuming dirty, and often difficult for the operator, particularly if he/she is of small physical stature or handicapped. Performing the task may also increase the potential for operator injury.
It would be desirable to provide an apparatus that would simplify the connection of an implement to a quick coupler and automatically engage a PTO connection simultaneous with engagement of the quick connecting hitch latching mechanism.